测试下列命令：

wget https://github.com/datalad/example-dicom-structural/raw/master/dicoms/N2D_0001.dcm

显示下列错误：

OpenSSL: error:14077410:SSL routines:SSL23_GET_SERVER_HELLO:sslv3 alert handshake failure 

Unable to establish SSL connection.

原因是：

As written on the project page of wget, the secure protocols TLSv1_1 and TLSv1_2 were added in wget version 1.16.1. Your wget 1.15 does not support it.

wget1.15版本不支持HTTPS

于是升级wget：

brew install wget

显示成功安装版本1.19.5

检查wget的版本：

wget –version

wget –versionGNU Wget 1.15 built on linux-gnu.+digest +https +ipv6 +iri +large-file +nls +ntlm +opie +ssl/openssl

怎么还是1.15版本？怎么回事呢？

which wget

/usr/local/bin/wget

查找wget

find /usr/ -name “wget” 

/usr//local/bin/wget

/usr//local/Cellar/wget

/usr//local/Cellar/wget/1.19.5/bin/wget

这是什么鬼？存在多个版本！原来brew安装的文件不在/user/local/bin的目录下

删除系统默认版本：

sudo rm -f /usr/local/bin/wget

解决:

sudo cp /usr/local/Cellar/wget/1.19.5/bin/wget /usr/local/bin/

再来测试：

wget https://github.com/datalad/example-dicom-structural/raw/master/dicoms/N2D_0001.dcm